Diesel emissions filtering system and method

ABSTRACT

The invention is embodied in an emission control system for reducing diesel particulate matter (DPM) from diesel engine exhaust gases comprising an aqueous filter apparatus constructed and arranged to form a water bath for all exhaust gas output from the engine and including in the water bath a preselected significant quantity of a low foaming wetting composition having a high affinity for hydrocarbons. The invention is further embodied in a diesel emissions filtering method including pre-filtering diesel fuel and removing DPM from exhaust gases by filtration through an aqueous solution having a low foaming wetting composition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a non-provisional of U.S. application Ser. No. 60/551,086, filedMar. 8, 2004, the entire disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to diesel fuel control systems, andmore particularly to diesel systems and methods for reducing hydrocarbonand diesel particulate matter levels in diesel exhaust emissions toassure safe environmental operation of diesel engines.

2. Description of the Prior Art

Internal combustion engines are designed to operate most efficiently onstandard quality fuels, and the presence of impurities ornon-combustible contaminates may result in poor engine performance orimpairment as well as produce higher levels of exhaust impurities. Evensmall quantities of water in diesel fuel may prevent satisfactoryoperation of a diesel engine, and most diesel engines now have some typeof water-separator in addition to filters for removing sediment or othersolids that may have been introduced into the fuel tank. It is also nowknown that the presence of air entrained in diesel fuel delivered to afuel injection system results in poorer engine performance since theamount of air required for optimum combustion is already preciselycontrolled by the fuel injection system itself. It is thus clear thatthe presence of these non-fuel contaminates in a diesel fuel deliverysystem result in poor engine performance with the extended result ofless complete fuel burning and an increase in deleterious exhaustpollutants.

During operation diesel engines produce various exhaust pollutantsincluding unburned hydrocarbons, carbon and nitrogen oxides, sulfurousgases and other particulate matter generally called “diesel particulatematter” (DPM). Aside from the environmental interests in reducing suchair pollution generally, there is an absolute necessity of doing so incertain diesel operating environments. There is a prevalent use ofdiesel engine powered equipment in fiery gaseous mining applicationswhere methane gas is present; and the Federal government, through theMine Safety Health Administration (MSHA), has set rigid regulations forthe design and operation of such diesel engines (particularly for class32 machinery that operates underground in the vicinity of the miningcut—as opposed to class 24 equipment which operates outby or outdoors infresh air). Thus the preparation or modification of diesel engines foruse in class 32 gaseous applications has reference to flame paths, skintemperatures of engine and attachments, final exhaust temperatures andfinal exhaust gas emission analysis and shut-down systems.

A primary troublesome area has been the control of exhaust gasemissions, and the Federal government has heretofore mandated the use of“soot trap filters” to reduce DPM emissions exhaust levels by filteringhydrocarbons out of the diesel exhaust gases. However, the use of dryfilter soot traps on the end of a diesel exhaust has generally posed afire hazard problem irrespective of what the filter material (steel,fibreglass, ceramic, etc.) is made of, since the accumulation of DPMhydrocarbons at normal engine and exhaust operating temperatures maycause an explosion in a gaseous coal mine. For instance, diesel enginecombustion temperatures may be 800°-1100° F., so significant engine andexhaust pipe cooling should be effected to reduce gas emissionstemperatures below the ignition temperature of hydrocarbon accumulationsin the soot trap. High exhaust gas temperatures are especially hazardousin the operation of class 32 diesel engines in coal mines or like closedenvironments where methane gas may be present since methane has anignition temperature of 302° F. In past practice, the exhaust lines fromclass 32 diesel engines have been insulated with “Thermogram” or thelike so that the high (800° F.) combustion temperature would be carriedby diesel exhaust gases past the catalytic converter to the soot trapthus producing the probability of fires and/or explosions therein withthe result that mine operators refuse to use the mandated soot traps forsafety reasons and generally continue to operate under violationcitations from the Mine Safety and Health Administration (MSHA), whichrecognizes the danger and reason for the continuing violation.

It has been reported that the mandated dry soot traps are still firehazards even after the engine is shut off because oxygen will flow fromambient back into the hot trap and ignite the carbon/hydrocarbon DPMaccumulation therein. In short, any dry soot trap per se almost alwaysposes a fire hazard and, in addition, soot traps are labor intensive andexpensive.

In the past the foregoing fire hazard problem has been approached byattempting to provide exhaust gas cooling means, generally in the formof a so-called gas scrubber consisting of a body of water into which theexhaust gases were passed and cooled. Typical of the prior art directedto such water scrubbers are the following U.S. Pat. No. 3,957,467granted May 18, 1976 (Kim); U.S. Pat. No. 3,976,456 granted Aug. 24,1976 (Alcock); and U.S. Pat. No. 4,190,629 granted Feb. 26, 1980(Strachan). However, the apparatus of these patents primarily only coolsthe exhaust gas, but has no other major effect since only a smallportion of DPM matter will be trapped in plain hard mine water, and alsono significant carbon monoxide will be removed. The Kim U.S. Pat. No.3,957,467 states that a gas purification liquid may be used and, inaddition to water alone, it is suggested that aqueous solutions mayinclude other non-specific additives such as detergent, surfactant orwetting agents, alcohol, glycol or alkalis.

SUMMARY OF THE INVENTION

The invention is embodied in an emission control system for cleaningdiesel particulate matter (DPM) from diesel engine exhaust gases andcomprising an aqueous filter apparatus forming a water bath having amajor water portion with a minor portion of super-wetting agent(“wetting composition”) having a high affinity for hydrocarbons. Theinvention is further embodied in a diesel emissions filtering methodincluding the features of pre-filtering diesel fuel, and removing DPMfrom diesel exhaust gases comprising filtering such gases through anaqueous solution having a minor portion of a low foam super-wettingagent, and finally filtering the exhaust gases.

A principal object of the invention is to provide systems, apparatus andmethods for removing significant amounts of diesel particulate matterfrom diesel exhaust gases prior to final discharge thereof to ambient.

Another object is to substantially reduce carbon monoxide levels in thefinal emission gases prior to discharge to ambient.

An object of the invention is to provide a diesel filtering methodcomprising pre-filtering diesel fuel to remove non-combustible matterupstream of the engine, removing DPM and carbon monoxide from dieselexhaust gases downstream of the engine, and final filtering the exhaustgases before discharge to ambient.

Another object of the invention is to provide more effective ways ofremoving DPM and carbon monoxide matter from diesel exhaust gases usinglow cost systems and equipment and labor saving methods.

It is another objective to greatly improve the working environmentaround diesel powered equipment, particularly in coal mines and likeunderground sites with potential methane gas or other hazardous gaspresence.

Another object is to provide exhaust gas scrubber systems and methodsthat are effective in removing DPM matter and carbon monoxide fromdiesel exhaust gases prior to passing to a final filter, as presentlymandated by MSHA, and which will thereby prolong the useable life andreduce the costs of using such final filters. It is a still furtherobject to provide such systems, apparatus and methods whereby thepresent requirements for final exhaust filters may be changed inrecognition that such final filters are no longer needed.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings wherein like numerals refer to like partswherever they occur:

FIG. 1 is a diagrammatic view showing a diesel engine fuel systemembodying one aspect of the invention from fuel tank to emissionsexhaust;

FIG. 2 is an enlarged diagrammatic view of the emissions exhaustfiltering section of the system.

FIG. 3 is a diagrammatic view illustrating another embodiment of anemissions exhaust filtering section of the invention;

FIG. 4 is another diagrammatic view showing a further embodiment of theexhaust filtering section; and

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the diagrammatic overview of a diesel fuel system of theinvention as shown in FIG. 1, this system includes a fuel deliverysection FD between the fuel tank 10 and the diesel engine 12 and anemissions exhaust section EE from the engine 12 to ambient.

One feature of the invention is to deliver a substantially pure dieselfuel to the engine, i.e., fuel that is free from air, water and otherunwanted gases or non-combustible contaminates. Thus, in the preferredembodiment, the fuel delivery section FD of the diesel system includesfuel pre-filtration means including a water filtration or separator unit14 connected by fuel line 15 to the fuel tank 10, and a particlefiltration unit 18 connected in line 17 through fuel pump 20 to thewater filter 14. In this preferred embodiment the water filter unit 14and particle filter unit 18 form a primary or initial fuel filter means21, and a secondary fuel filter means 22 is connected through a flowrate regulator valve 24 in line 23 to the primary filtration means 14,18.

The secondary fuel filter 22 includes a vessel 26 having an interiorseparation chamber 27 constructed and arranged to fluidically connectthrough delivery line 28 to the fuel injection system (not shown) forthe engine 12, and also has a return line 29 connecting back to the fueltank 10. An air purge means (not shown) can be provided at the top ofthe vessel 26 to bleed air out of the fuel delivery system. U.S. Pat.Nos. 5,746,184 and 5,355,860 are incorporated by reference as disclosingfeatures of one suitable pre-filtration means of the fuel deliverysection FD in greater detail.

In operation, the fuel delivery section FD provides for the positivedelivery of diesel fuel from the fuel tank 10 to the injection system(not shown) of diesel engine 12. Pump 20 assures positive flow throughboth the primary and secondary fuel filter means 21, 22 in which air,water and other non-fuel impurities are removed. Thus, optimum engineperformance can be achieved through pre-filtration of diesel fuels withthe result that maximum burning of diesel fuel will result in lowerlevels of diesel particulate matter (DPM) in the emission exhaust gasesfrom the engine 12. Nonetheless, the unburned hydrocarbon content ofengine exhaust gases has, in the past, continued to be a major safetyand health concern in the operation of diesel engines—particularly inclosed, poorly ventilated areas such as underground mines.

The major feature of the invention is to deliver diesel engine dischargegases (with inherent hydrocarbon DPM content) through the emissionexhaust section EE, which includes exhaust gas scrubber means for safelyremoving such DPM content, reducing carbon monoxide levels anddischarging cleaned exhaust gases to ambient. The effectiveness of thisfeature of the invention is achieved primarily by providing an aqueoussolution in the gas scrubber section EE that includes a super-wettingagent (“wetting composition”), and the following definitions will beinstructive in the disclosure and claiming of this feature of theinvention:

DPM (diesel particulate matter) as used herein shall generally mean allforms of hydrocarbon and other carbonaceous matter, carbon or nitrogenoxides, sulfurous gases and related particulate matter. DPM may also bereferred to as “particulate carbonaceous matter”.

Referring now again to FIG. 2 of the drawings, the exhaust scrubberportion EE of the system includes an aqueous filter apparatus positionedin the exhaust output passageway from the diesel engine 12 to ambient.More specifically, the aqueous filter apparatus forms a water bath WBthrough which all DPM laden exhaust gases are passed and cleaned beforebeing discharged to ambient. In a preferred form of the invention, thewater bath WB of filtering apparatus is contained in a scrubber tank 33that has an exhaust intake 34 connected by exhaust pipe 35 to theexhaust manifold (not shown) of the engine 12. The exhaust pipe 35 iscovered by a suitable insulation covering 36, such as “Thermogram”, toshield the high discharge gas temperatures (i.e., 800° to 1100° F.) fromthe surrounding ambient. In FIG. 2 it will be seen that the tank 33 hasan internal extension pipe 37 connected to the exhaust pipe 35 andextending into the tank 33 below the level 38 of the water bath WB. Agas discharge diffuser 39 is provided at the exit end of the exhaustextension pipe 37 to break up and disperse the exhaust gas stream as itis discharged from the extension 37 into the water bath WB in the tank33. For illustration purposes the diffuser 39 is simply shown as anelongate pipe having a series of discharge openings 40, but it will beunderstood that a wide variety of gas diffusing means, such as in theform of perforations, screens and turbulence producing means, may beemployed. The openings 40 are preferably arrayed along the length andaround the circumference of the diffuser 39. The diffuser means (39) ofthe invention should act to disperse or spread out the gas stream formixture into or percolation through the water bath WB and it may act topartially decelerate the entering gas stream to a lower velocity.However, it is important that any retardant effect should be controlledto a minimum so as to not create undue back pressure on the dieselengine 12.

The scrubber tank 33 may be any suitable shape, such as cubicle orcylindrical, and holds a pre-determined volume of liquid in the range of35 to 50 gallons. The exhaust intake 34 is located at one end of thistank, and the tank also has a gas discharge or outlet 42 located at theother tank end and positioned above the water bath level 38 in suchmanner that the exhaust gases must traverse through the water bath thelength of the scrubber tank 33 from the diffuser (40) at the intake endto the outlet port 42 at the exit end. A final filter 43 of ceramic orfiberglass is shown connected at the gas discharge outlet (as currentlymandated by MSHA for class 32 diesel operations). It is believed thatthe present invention will minimize any need for a final filter 43, aswill be shown.

In addition to the diffusing means (39, 40) for dispersing or breakingup the exhaust gas stream as it enters the water bath WB, the tank 34 isprovided with baffle means (44, 45) projecting vertically into the bodyof water in the tank and extending across the tank from side to side.The baffle means (44, 45) are constructed and arranged to createtortuous or circuitous gasflow pathways to increase the turbulence andmixing contact of DPM laden gas molecules with the water bath WB. In theform of the invention shown in FIG. 2, first baffles 44 are arranged toextend upwardly from the floor 46 of the tank or just above the floor,and have upper ends 44 a below the water level 38. Second baffles 45 arearranged to extend downwardly from the top 47 of the tank and have lowerend margins 45 a within the water bath and spaced above the floor 46.The first and second baffle means are alternately arranged to createmajor tortuous pathways having primary vertical channels therebetweenand being connected around the baffle end margins (44 a, 45 a), as shownby the curved arrows. The baffles 44, 45 are also shown with minorsecondary through-ports 49 to provide for small portions of exhaustgases to flow directly through these baffles and impinge on the majorgas portions flowing in a vertical direction in the primary verticalpassageways whereby to cause further turbulence and scrubbing actionbetween the gases and the water bath WB. It should be noted that thebaffles 45 extend across the tank from the top (47) downwardly into thewater bath thereby forming a vapor barrier or seal above the waterlineso that exhaust gases must flow through the water bath in the majorpassageways to reach the final exit port 42 from the tank 33. The tank33 also has a water fill pipe 50 and water level float 51, and thebottom of the tank may have an outlet 74 or like drain provision forperiodic flushing of the tank as may be required.

Super-wetting agent or wetting composition as used herein shallgenerally mean an aqueous mixture comprising a combination of a chemicalhydrocarbon cleaner and a defoaming agent, the composition typically inthe form of a colloid, suspension, emulsion or solution.

A colloid (i.e., colloidal system) as used herein shall generally mean adispersion of finely divided particles in a continuous liquid medium—theparticles being in a mid-size range between a true solution (1millimicron or nanometer) and a coarse dispersion or suspension (1micron or micrometer). Emulsion as used herein shall generally mean astable mixture of two or more immiscible liquids held in suspension by asurface-active “emulsifier” that is either (1) a protein or carbohydratepolymer which coats the surfaces of dispersed fat (oil) particles toprevent coalescing (called a protective colloid) or (2) a long-chainalcohol and fatty acid which reduces surface tension at the interface ofsuspended soluble particles. Emulsions consist of a continuous phase anda disperse phase in which small globules of one liquid are suspended ina second liquid by a wetting or deterging agent.

An important aspect of the invention resides in the selection ofsuitable combination of chemical hydrocarbon cleaner and defoaming agentto formulate an acceptable wetting composition for use in the aqueousmixture of the water bath WB. In the past water scrubbers have beenplaced in diesel exhaust lines to cool exhaust gases and, of course,some amount of particulate soot materials will be removed from thesegases. However, it is known that the carbonaceous matter or DPM isbasically immiscible in water and that only a very small portion of DPMwill be suspended in the water of these prior art traps; and that nocarbon monoxide will be removed therein. Thus, it is presently mandatedthat all scrubbers (soot traps) of any kind used on class 32 dieselequipment in coal mines be equipped with a “stop work float device” toensure that hydrocarbon sludge in the tank does not reach kindlingtemperature and catch fire. It is also known that various natural andchemical surfactants, detergents and/or wetting agents in aqueoussolution can attract hydrocarbons from exhaust gases and hold them inthe water of a scrubber, but the resulting foaming action of suchadditives often creates unacceptable conditions and environmentalproblems.

It will be understood that the wetting composition of the inventionshould preferably be able to function effectively in hot environments(e.g., about 800° to 1100° F.), which is the typical temperature rangeof exhaust gases entering the aqueous solution of the scrubber (33).Furthermore, the wetting composition should desirably be able to reactvery fast and bond with hydrocarbons and carbon compounds and pull themfrom the exhaust gases. It is believed that the high gas temperature mayact to accelerate this bonding reaction of the chemical hydrocarboncleaner (e.g., surfactant) with the DPM and also the removal of carbonmonoxide (CO) from the exhaust stream. The turbulence generated by therapid flowing exhaust gases entering the scrubber and being dispersed bythe diffuser through the water bath produces greater surface areacontact and more complete removal of DPM and CO from the exhaust.

The chemical hydrocarbon cleaner is preferably selected so as to be ableto reduce the amount of DPM and CO present in the exhaust gas enteringthe scrubber. In addition, a suitable wetting composition of the presentinvention has a fast reaction in attracting and holding DPM due to thehigh velocity of the exhaust gas stream entering the scrubber tank (33),even though the diffuser means (39) may have a retardant effect on thedispersed gas. In one embodiment, the present invention attracts andholds the DPM 3 to 5 times or even faster than previous scrubbingmethods.

In accordance with one embodiment of the present invention, variouswetting compositions have been devised for use in conjunction with adiffusing means for dispersing exhaust gases throughout the water bathof a scrubber, thereby obviating prior art shortcomings and achievingsuperior diesel exhaust gas cleansing of DPM and reduction of carbonmonoxide levels.

The chemical hydrocarbon cleaner may be suitably selected from variousdetergents, soaps, surfactants and mixtures thereof. Detergent as usedherein generally means any deterging or cleaning agent produced fromsynthetic organic compounds (rather than natural fats or oils and alkalias in soaps). Detergents are soluble in water, and highly foamable andact as a wetting agent and emulsifier.

In one embodiment, the chemical hydrocarbon cleaner used in the presentinvention may include a soap. Soap as used herein shall generally mean adeterging or cleaning agent made by reacting a natural fatty acid (e.g.,tall oil fatty acid) or oil with an alkali or caustic (such as sodium orpotassium hydroxide or an alkanolamine such as monoethanolamine) toproduce the corresponding soap with glycerol as a by-product. Soaps,like detergents, exhibit surface-active properties, such as foaming,detergency and lowering of surface tension.

Surfactant as used herein shall mean any of the class of surface-activeagents including (or are included in) detergents, soaps, colloids andemulsifiers. Surfactants are surface-active agents that reduce thesurface tension of water and cause it (1) to penetrate more easily into,or spread over the surface of, another material or (2) be penetrated byor become a dispersion of another material. Surfactants are wettingagents that orient themselves at the molecular interface of water withother surfaces and modify the liquid properties at the interface. Asurfactant typically consists of two parts: a hydrophobic portion (e.g.,a long hydrocarbon chain) and a hydrophilic portion that makes theentire compound soluble or dispensable or dispersable in water and thesehydrophobic and hydrophilic moieties render the compound surface-active.Surfactants suitable for use in the practice of the present inventionare generally classified as anionic, cationic, nonionic, or amphoteric.

Preferably, in order to alleviate environmental concerns, the wettingcomposition is formulated to be phosphate and nitrate-free. Furthermore,the chemical hydrocarbon cleaner is preferably low-foaming to mitigateproduction of foam during use. Nonionic surfactants generally have lowersudsing or foaming characteristic than anionic surfactants (cationicsurfactants are primarily used in industrial chemical processing).Accordingly, in view of these concerns, in a preferred embodimentdescribed in greater detail below, the chemical hydrocarbon cleanerutilized in the wetting composition comprises a nonionic surfactant.

Examples of suitable nonionic surfactants for use in the chemicalhydrocarbon cleaner component of the wetting composition includeethoxylated alcohols, alkanolamines, and mixtures thereof. In accordancewith a preferred embodiment, the chemical hydrocarbon cleaner includesan ethoxylated nonylphenol nonionic surfactant, for example, n-molarethoxylated nonylphenols or mixtures thereof, sometimes denoted asnonoxynol-n, where n is a rational number between about 2.5 and about15. Such nonionic surfactants are available from Huntsman Chemical (SaltLake City, Utah). In an especially preferred embodiment, the ethoxylatednonylphenol nonionic surfactant comprises nonoxynol 10 either alone orin combination with an alkanolamine nonionic surfactant such asmonoethanolamine.

Even in embodiments where a low-foaming nonionic surfactant is employedas the hydrocarbon cleaning agent, the wetting composition of thepresent invention advantageously further includes a defoaming agent.Indeed, the use of a defoaming agent is an important aspect of theinvention in that it provides a wetting composition that does not foamexcessively, in short, that it maintain a substantially liquid state atall times. Known defoaming agents have a variable range ofeffectiveness. Accordingly, the concentration of the defoaming agent inthe wetting composition may vary considerably in order to attainsuitable mitigation of foam production during use, but generally is atleast about 1% by weight, more typically at least about 5% by weight andpreferably from about 5% to about 15% by weight. The concentration ofthe defoaming agent in the wetting composition necessary to obtain thedesired results under applicable operating conditions can be readilydetermined through routine experimentation.

The defoaming agent typically is dispersable in the other components ofthe wetting composition. Examples of suitable defoaming agents includepetroleum-based antifoams (e.g., 2-octanol, sulfonated oils, organicphosphates) and silicone-based antifoams. However, it has been foundthat petroleum-based antifoams may be susceptible to degradation in thewetting compositions disclosed herein and may not provide the desiredlevel of foam mitigation during use after prolonged periods (e.g., 1 to2 days) following formulation. Accordingly, in such embodiments, thewetting compositions can be prepared for use in aqueous solution as asingle or one part product; or the remainder of the composition can bepackaged separately from the petroleum-based antifoam to be combinedwith the remainder of the composition just prior to use at the dieseloperating site. In order to provide a wetting composition capable ofsufficient foam mitigation and longer effective shelf-life, it ispreferred that a silicone-based antifoam be utilized as the defoamingagent. Specific examples of silicone-based antifoams include siliconefluids and organosiloxanes. In accordance with an especially preferredembodiment, the defoaming agent comprises a polydimethylsiloxane.Non-limiting examples of suitable polydimethylsiloxane antifoams includethose available from General Electric (Waterford, N.Y.), such as thosesold under the product designations AF9000, AF9010, AF9020 and AF9030.

In one preferred embodiment wherein the chemical hydrocarbon cleanercomponent comprises a nonionic surfactant comprising an ethoxylatednonylphenol in combination with monoethanolamine or other alkanolamine,the wetting composition may advantageously be formulated with a tall oilfatty acid. In such an embodiment, the tall oil fatty acid is saponifiedat least to some extent with the alkanolamine caustic to form a soap.

The wetting composition of the present invention may include a varietyof optional components in addition to the chemical hydrocarbon cleanerand the defoaming agent. For example, the composition, particularly whena surfactant (e.g., a nonionic surfactant) is utilized as the chemicalhydrocarbon cleaner, may further include an organic solvent. In suchembodiments, the organic solvent may provide composition thinning orfluidity, for example, in the form of a colloid. Suitable non-limitingexamples of organic solvents include alkylene glycol ethers such asdipropylene glycol methyl ether.

It may also be advantageous to include in the wetting composition acoupling agent such as tetrasodium ethylenediaminetetraacetate (EDTA) asa formulation aid.

One representative preferred wetting composition useful in treatingdiesel exhaust emission gases in accordance with the present inventioncomprises water; a chemical hydrocarbon cleaner comprising ethoxylatednonylphenol nonionic surfactant and a soap formed by saponifying a talloil fatty acid with monoethanolamine; an organic solvent comprisingdipropylene glycol methyl ether; a coupling agent comprising tetrasodiumEDTA; and a defoaming agent comprising a silicone-based antifoam.Preferably, the ethoxylated nonylphenol nonionic surfactant comprisesnonoxynol 10 and the silicone-based antifoam comprises apolydimethylsiloxane.

Another more representative preferred wetting composition in accordancewith the present invention comprises at least about 35% by weight water;a chemical hydrocarbon cleaner comprising an ethoxylated nonylphenolnonionic surfactant and a soap formed by saponifying a tall oil fattyacid with monoethanolamine, wherein the composition comprises from about10% to about 30% by weight ethoxylated nonylphenol nonionic surfactant,from about 2% to about 8% by weight tall oil fatty acid and from about1% to about 5% by weight monoethanolamine; an organic solvent comprisingdipropylene glycol methyl ether, wherein the composition comprises fromabout 5% to about 15% by weight dipropylene glycol methyl ether; acoupling agent comprising tetrasodium EDTA, wherein the compositioncomprises at least about 0.5% by weight tetrasodium EDTA; and adefoaming agent comprising a silicon-based antifoam, wherein thecomposition comprises at least about 1% by weight silicon-basedantifoam. Preferably, the ethoxylated nonylphenol nonionic surfactantcomprises nonoxynol 10 and the silicone-based antifoam comprises apolydimethylsiloxane.

Examples of wetting compositions in accordance with the presentinvention include the products designated Aqua Filter Nos. 195D, 942Dand 735D available from Brady's Mining and Construction Supply Co. (St.Louis, Mo.). These wetting compositions each have a multiple surfactantbase of low foaming surfactants plus a silicone-based antifoam.

Methods and techniques for formulating wetting compositions inaccordance with the present invention will be readily apparent to thoseskilled in the art. Generally, water, the chemical hydrocarbon cleanerand the defoaming agent along with any other components of the wettingcomposition are blended in a suitable vessel equipped with an agitationdevice (e.g., a stirred tank). Typically, it may be necessary to heatthe mixture or the individual components thereof in order to produce thedesired composition in the form of a colloid, suspension, emulsion orsolution.

In formulating these preferred wetting compositions of the presentinvention it may be useful to start with the colloidal surfactant blenddesignated B/F100P, available from Foresight Chemical (Troy, Ill.) andBrady's Mining and Construction Supply Co. (St. Louis, Mo.). Thisproduct comprises a colloid containing nonoxynol 10, dipropylene glycolmethyl ether, monoethanolamine, tall oil fatty acid and tetrasodiumEDTA. Accordingly, B/F100P can be used as a suitable base forformulating the wetting composition described herein. In one embodiment,a suitable quantity of defoaming agent (e.g., polydimethylsiloxane) maybe added to produce the wetting composition. However, in order toprovide a more effective wetting composition having desirable fluiditycharacteristics, it is preferred to add additional quantities ofnonoxynol 10 and tall oil fatty acid as necessary to obtain the desiredcomposition as set forth above along with the defoaming agent.Preferably the B/F100P base composition is heated to a temperature offrom about 125° to about 175° F. during addition of these ingredients.Typically, additional dipropylene glycol methyl ether is added in orderto thin the composition and ensure sufficient fluidity in the finalwetting composition. For example, in one embodiment, a suitable wettingcomposition may be prepared by mixing approximately 70 parts by weightof B/F100P with approximately 30 parts by weight of a low foamingsurfactant including approximately 10 parts by weight of asilicone-based defoaming agent.

Although a preferred wetting composition as described above includes anethoxylated nonylphenol nonionic surfactant as the chemical hydrocarboncleaner, those skilled in the art will be able to identify othersurfactants, detergents, soaps and mixtures thereof for use incombination with a defoaming agent. Examples of such chemicalhydrocarbon cleaners include the surfactants found in JOY branddishwashing liquid (Procter and Gamble, Cincinnati, Ohio) and PALMOLIVEbrand dishwashing liquid (Colgate-Palmolive, New York, N.Y.). Suitableanionic surfactants include alkylether sulfates, alkyl sulfates andmixtures thereof.

In accordance with the present invention, the DPM level of the exhaustgas entering the scrubber can be reduced by at least about 30% and thecarbon monoxide loading reduced to an acceptable level (e.g., 13 ppm).In one preferred embodiment, the DPM level can be reduced in the rangeof from about 40% to about 80%. In an even more preferred embodiment,the DPM level can be reduced by from about 60% to about 80% or evenhigher levels of reduction. In addition, up to about 99% of DPM can beremoved when the water bath scrubber (33) is used in conjunction with afinal filter (43).

The scrubber tank 33 of the FIG. 2 embodiment holds a water bath havinga major water constituent (e.g., typically from about 25 to about 50gal.) and a minor constituent amount (e.g., typically from about 1 toabout 2 qts.) of the wetting composition disclosed herein (e.g., asolution of about 0.5% to 2%). Clearly, higher concentrations of thewetting composition in the water bath will perform to attract and holdmore DPM over longer operating periods. It should be noted that flushingof the tank (33) and replacement of the aqueous solution periodically(e.g., in the range of about 4 to 6 hours) will be required for optimumperformance to achieve “clean air” objectives. This is a low cost, highsatisfaction result as compared with the high cost of present prior artsystems.

Referring now to FIG. 3, another form of the invention is showndiagrammatically as an exhaust scrubber EE having a scrubber apparatusconstructed and arranged to provide a continuous water bath replacementprocess. In the FIG. 3 embodiment the scrubber tank 133 is relativelysmall and has a capacity for holding about 4 gallons of the aqueoussolution. Similar to the FIG. 2 embodiment, in FIG. 3 the insulateddiesel exhaust pipe 135 connects from the engine (12) to the tank 133 ata gas intake 134, and an internal extension pipe 137 extends below thetank's water level 138 and has a perforated gas discharge diffuser 139for dispersing the DPM laden exhaust gas as it is discharged into thewater bath WB. The diffuser 139 is shown as discharging exhaust gasradially, outwardly through the water bath, but other gas dispersingmeans may be arranged in the water bath. The tank 133 also has a gasdischarge outlet 142 located above the water level 138. The feature ofthe FIG. 3 embodiment is that the aqueous solution of the water bath WBhas a continuous feed and is constantly flowing into and through thetank 133 to intimately mix with exhaust gases and remove DPM and carbonmonoxide from such exhaust gases.

FIG. 3 shows that the aqueous solution can be prepared by admixing aminor portion of super-wetting agent with a major quantity of water asin a blending tank or mixer 170 constructed to hold a large amount ofsolution, such as 45 to 55 gal. and from which the flow rate of thewater bath solution into tank 133 can be regulated, as at 171. Thesuper-wetting aqueous solution is delivered into the tank through adelivery tube or pipe 172 and discharged through a perforateddistributor 173 outwardly in radial directions to maintain level of thewater bath WB, in such manner that the exhaust gases as a first medium,are dispersed into or throughout the water bath even as the incomingaqueous solution, as a second medium, is being dispersed therein toachieve the desired intimate turbulence and intermixing whereby thesuper-wetting agent removes the DPM and cleans the exhaust gases. Thus,the water bath WB of FIG. 3 is not static as the tank 133 has an outlet174 for regulating the out flow drainage of the aqueous solution fromthe tank 133 at the predetermined rate so that the solution isconstantly flowing into and replacing the water bath content as it isdischarged from the tank.

Still referring to FIG. 3, the small volume tank 133 is provided withthe baffle means 144 extending upwardly from adjacent the floor 146 andbaffle means 145 extending down from the top of the tank 133 to enhancecircuitous gas flow paths. Through-ports 149 may also be provided inthese baffles 144 to increase turbulence and intermixing of the exhaustgases with the aqueous solution. The baffles 145 form vapor seals abovethe level of the water bath in the tank 133 to force the exhaust gas topass through the water bath to the exhaust.

It should be noted that the effluent solution from outlet drain 174 canbe piped off for remote disposal. However, in most underground miningoperations, as in coal mining, water is widely used for differentpurposes by different equipment, and it is usually discharged aswastewater onto the mining floor where it will be absorbed or from whichit may or may not be removed by gravity run-off or through sump action.For instance, water is used in drilling and cutting operations as acoolant for rotary drill bits, long-wall cutting teeth and the like—aswell as to remove and flush cuttings away from the drilling or cuttingsite. Respirable dust is a health threat even as DPM environmental airpollution is a concern addressed by the present invention. Therefore,water is used as a dust suppressant and the disposal methods foreffluent mine water from the various diesel systems or other miningequipment are a general concern, but outside the scope of the invention.

Referring to FIGS. 4 and 5, the invention can be carried out in anexhaust scrubber apparatus (EE) having a sealed scrubber tank jacket orhousing 233 with an exhaust gas inlet 234 from diesel exhaust pipe 235at one side and clean gas outlet 242 at the other side. In thisembodiment the aqueous solution is discharged in a plurality of adjacentvertical streams (280) as a continuous water bath curtain from the topwall 247 across the width of the scrubber tank 233 to the floor 246 fromwhich the effluent is removed through an outlet drain 274 for disposal.The aqueous solution formed by mixing a super-wetting agent of theinvention with water, as in blending tank or mixer 270, is deliveredthrough a flow regulator 271 to a distributor manifold 281 or the likefrom which it is piped to one or more horizontal perforated pipes 282.The diffuser 239 for spreading out the discharge of exhaust gases in thescrubber tank chamber is constructed and arranged to have a maximum gasdischarge area to provide the widest gas dispersion through and intimatecontact with the aqueous solution as it passes through the verticalcurtain wall of the water bath WB.

The aqueous solutions used in the FIG. 3 and FIG. 4 embodiments will bethe same as previously discussed, and only the respective delivery andmixing of exhaust gases therewith is different.

It is now apparent that the objects and advantages of the presentinvention have been fully met. Changes and modifications of thedisclosed forms and combinations of the invention will become apparentto those skilled in the mining field and the providers and operators ofdiesel equipment in general, and the invention is only to be limited bythe scope of the appended claims.

1. An emission control system for reducing diesel particulate matter(DPM) from the exhaust gas output from a diesel engine, comprising anaqueous filter apparatus positioned in the exhaust output passagewayfrom the diesel engine and being constructed and arranged to form awater bath in said passageway through which all DPM laden exhaust gasesfrom said engine must pass before being discharged to ambient, the waterbath of said aqueous filter apparatus comprising water as a majorconstituent and a wetting composition as a minor constituent, saidwetting composition comprising a chemical hydrocarbon cleaner includingat least one component selected from the group consisting of detergents,soaps, surfactants and mixtures thereof, and a defoaming agent.
 2. Theemission control system of claim 1, in which said aqueous filterapparatus comprises a gas scrubber tank filled to a predetermined levelwith said water bath, said exhaust output passageway having a dischargeend positioned below the level of said water bath, and gas diffusingmeans in said tank for dispersing exhaust outflow gases throughout thewater bath.
 3. The emission control system of claim 2, wherein said gasdiffusing means comprises a perforated gas discharge pipe at thedischarge end of said passageway whereby to effect percolation ofexhaust gases through the water bath.
 4. The emission control system ofclaim 2, in which said gas scrubber tank has an exhaust discharge outletto ambient, and wherein said gas diffusing means comprises verticalbaffle means disposed in said gas scrubber tank between the dischargeend of said exhaust output passageway into the water bath and saidexhaust discharge outlet to thereby produce circuitous flow paths ofexhaust gases through the water bath in said tank.
 5. The emissioncontrol system of claim 4, wherein said vertical baffle means includesplural horizontal ports extending therethrough to provide limitedby-pass flow of exhaust gases across said circuitous gases flow paths.6. The emission control system of claim 2, in which said gas scrubbertank has an exhaust gas inlet end receiving the exhaust outputpassageway from the engine, and having an exhaust gas outlet end abovethe level of the water bath and forming a gas discharge outlet toambient, said gas diffusing means for dispersing including at least twomixing means for creating circuitous and turbulent flow of exhaust gasesthrough said water bath.
 7. The emission control system of claim 6,wherein one of said mixing means comprises a perforated gas dischargepipe on the inlet side of said scrubber tank for discharging of exhaustgases from said exhaust output passageway through the water bath.
 8. Theemission control system of claim 6, wherein one of said mixing meanscomprises a plurality of baffles between the inlet and outlet ends ofsaid scrubber tank to circulate exhaust gases intimately throughout thewater in serpentine flow paths around and between the baffles.
 9. Theemission control system of claim 8, including another mixing means inthe form of ports through the baffles to accommodate minor limiteddirect flow of a portion of exhaust gases through the baffles in adirection substantially perpendicular to the serpentine flow directionof exhaust gases around and between the baffles.
 10. The emissioncontrol system of claim 1, including water level sensing means forassuring safe operating water levels of said water bath.
 11. Theemission control system of claim 1, in which said aqueous filterapparatus comprises water curtain means for discharging an aqueous waterwall formed of a solution of said major body of water and minor amountof super-wetting agent.
 12. The emission control system of claim 11, inwhich said water curtain means comprises closed scrubber tank meanshaving a gas inlet side connecting to the engine and a gas dischargeside connecting to ambient, a supply source of blended water and wettingcomposition, and water spray means for discharging a continuouslyflowing curtain wall of such solution across the tank means, and saidgas inlet side having gas dispersing means for discharging exhaust gasesfrom the engine throughout the upstream inlet side for passage therefromthrough the curtain wall to the downstream outlet side.
 13. The emissioncontrol system of claim 12, in which said supply source hold arelatively large amount of blended water and wetting composition andsaid scrubber tank means is relatively small, and said scrubber tankmeans including discharge means for outflowing used solution from thebottom thereof.
 14. The emission control system of claim 13, in whichsaid scrubber tank means has a volumetric capacity in the range of 4 to10 gal. and said supply source of solution comprises a solution blendingtank having a volumetric capacity in the range of 25 to 60 gal.
 15. Theemission control system of claim 12, including means for regulating theflow of solution to said water spray means.
 16. The emission controlsystem of claim 2, in which said aqueous filter apparatus comprises agas scrubber tank of relatively large size holding a water bath in thevolumetric range of 25 to 55 gal.
 17. The emission control system ofclaim 2, in which said gas scrubber tank has a relatively small sizeholding a water bath in the volumetric range of 3 to 10 gal., and asupply source of blended water and wetting composition solutionconstructed and arranged for maintaining the water bath level in saidscrubber tank.
 18. The emission control system of claim 1, incombination with a diesel fuel pre-filter constructed and arrangedupstream of the diesel engine for removing non-fuel contaminates fromthe diesel fuel to thereby improve engine performance.
 19. The emissioncontrol system of claim 18, in which said fuel pre-filter is interposedin the fuel supply line to the diesel engine, and is constructed forfiltering non-combustible contaminates of the diesel fuel whereby toprovide a substantially totally-combustible diesel fuel supply to theengine.
 20. The emission control system of claim 19, in which said fuelpre-filter includes a first filter for filtering water out of the dieselfuel, and a second filter for filtering air out of the diesel fuel. 21.The emission control system of claim 1, in which the wetting compositionis phosphate-free.
 22. The emission control system of claim 21, in whichthe wetting composition is nitrate-free.
 23. The emission control systemof claim 1, in which the chemical hydrocarbon cleaner is low-foaming.24. The emission control system of claim 23, wherein the chemicalhydrocarbon cleaner comprises at least one surfactant selected from thegroup consisting of anionic surfactants, cationic surfactants, nonionicsurfactants, amphoteric surfactants and mixtures thereof.
 25. Theemission control system of claim 23, wherein the wetting compositionfurther comprises an organic solvent.
 26. The emission control system ofclaim 25 wherein the chemical hydrocarbon cleaner comprises an anionicsurfactant.
 27. The emission control system of claim 26 wherein theanionic surfactant is selected from alkylether sulfates, alkyl sulfatesand mixtures thereof.
 28. The emission control system of claim 25wherein the chemical hydrocarbon cleaner comprises an amphotericsurfactant.
 29. The emission control system of claim 25 wherein thechemical hydrocarbon cleaner comprises a nonionic surfactant.
 30. Theemission control system of claim 29 wherein the nonionic surfactant isselected from the group consisting of ethoxylated alcohol, alkanolaminesand mixtures thereof.
 31. The emission control system of claim 30wherein the nonionic surfactant comprises an ethoxylated nonylphenol.32. The emission control system of claim 31 wherein the nonionicsurfactant comprises a mixture of an ethoxylated nonylphenol and analkanolamine.
 33. The emission control system of claim 32 wherein thenonionic surfactant comprises a mixture of an nonoxynol 10 andmonoethanolamine.
 34. The emission control system of claim 31 whereinthe organic solvent comprises an alkylene glycol ether.
 35. The emissioncontrol system of claim 34 wherein the organic solvent comprisesdipropylene glycol methyl ether.
 36. The emission control system ofclaim 31 wherein the defoaming agent is selected from petroleum-basedantifoams, silicone-based antifoams and mixtures thereof.
 37. Theemission control system of claim 36 wherein the defoaming agentcomprises a silicon-based antifoam.
 38. The emission control system ofclaim 37 wherein the silicon-based anti-foam comprises anorganosiloxane.
 39. The emission control system of claim 38 wherein thesilicon-based anti-foam comprises polydimethylsiloxane.
 40. The emissioncontrol system of claim 31 wherein the wetting composition furthercomprises a coupling agent.
 41. The emission control system of claim 40wherein the coupling agent comprises tetrasodium EDTA.
 42. The emissioncontrol system as set forth 41 wherein the chemical hydrocarbon cleanercomprises a soap formed by saponifying a tall oil fatty acid with acaustic comprising an alkanolamine.
 43. The emission control system asset forth in claim 1 wherein the wetting composition comprises: water; achemical hydrocarbon cleaner comprising ethoxylated nonylphenol nonionicsurfactant and a soap formed by saponifying a tall oil fatty acid withmonoethanolamine; an organic solvent comprising dipropylene glycolmethyl ether; a coupling agent comprising tetrasodium EDTA; and adefoaming agent comprising a silicone-based antifoam.
 44. The emissioncontrol system of claim 43 wherein the ethoxylated nonylphenol nonionicsurfactant comprises nonoxynol
 10. 45. The emission control system ofclaim 44 wherein the silicone-based antifoam comprises apolydimethylsiloxane.
 46. The emission control system of claim 1 whereinthe wetting composition comprises: at least about 35% by weight water; achemical hydrocarbon cleaner comprising an ethoxylated nonylphenolnonionic surfactant and a soap formed by saponifying a tall oil fattyacid with monoethanolamine, wherein the composition comprises from about10% to about 30% by weight ethoxylated nonylphenol nonionic surfactant,from about 2% to about 8% by weight tall oil fatty acid and from about1% to about 5% by weight monoethanolamine; an organic solvent comprisingdipropylene glycol methyl ether, wherein the composition comprises fromabout 5% to about 15% by weight dipropylene glycol methyl ether; acoupling agent comprising tetrasodium EDTA, wherein the compositioncomprises at least about 0.5% by weight tetrasodium EDTA; and adefoaming agent comprising a silicon-based antifoam, wherein thecomposition comprises at least about 1% by weight silicon-basedantifoam.
 47. The emission control system of claim 46 wherein theethoxylated nonylphenol nonionic surfactant comprises nonoxynol
 10. 48.The emission control system of claim 46 wherein the silicone-basedantifoam comprises a polydimethylsiloxane.
 49. The emission controlsystem of claim 2, in which said gas scrubber tank has an exhaustdischarge outlet leading to ambient and, in combination therewith, afinal gas filter constructed and arranged to filter substantially allresidual DPM material from the cooled and cleaned exhaust gases passingfrom the gas scrubber tank.
 50. A diesel cleaning system for achievingoptimum diesel engine performance and maximum removal of DPM and CO fromdiesel exhaust emission gases, comprising the steps of: pre-filteringdiesel fuel upstream of a diesel engine to remove non-combustibles andenhance more complete fuel burning to minimize residual hydrocarboncontent in exhaust gases; dispersing diesel exhaust emission gasesthrough a water bath having water as a major constituent and as a minorconstituent a wetting composition comprising a chemical hydrocarboncleaner comprising at least one component selected from the groupconsisting of detergents, soaps, surfactants and mixtures thereof, and adefoaming agent, to thereby remove the majority of DPM matter from suchgases.
 51. A method of improving diesel engine performance and removingdeleterious materials from diesel fuel and diesel exhaust gases,comprising the steps of: pre-filtering diesel fuel upstream of theengine to remove non-combustible contaminates therefrom; filteringdiesel exhaust gases downstream of the engine to remove DPM and carbonmonoxide therefrom including the step of passing such exhaust gasesthrough an aqueous water bath having water as a major constituent and asa minor constituent a wetting composition comprising a chemicalhydrocarbon cleaner comprising at least one component selected from thegroup consisting of detergents, soaps, surfactants and mixtures thereof,and a defoaming agent.
 52. A DPM removal method for removing dieselparticulate matter (DPM) from the exhaust gas emission of diesel enginesused in class 32 gaseous environment applications, including the stepsof: providing water scrubber means downstream of the diesel engine toreceive exhaust gas outflow therefrom, providing an aqueous solution forthe water scrubber means comprising a water bath having water as a majorconstituent and as a minor constituent a wetting composition comprisinga chemical hydrocarbon cleaner comprising at least one componentselected from the group consisting of detergents, soaps, surfactants andmixtures thereof, and a defoaming agent, and creating an intimatedispersion of the exhaust gas emission through the aqueous solution ofthe water scrubber means.
 53. The method of cleaning carbonaceous matterfrom a first medium, comprising the steps of: selecting a chemicalhydrocarbon cleaner including at least one component selected from thegroup consisting of detergents, soaps, surfactants and mixtures thereof;selecting a defoaming agent as a secondary constituent; formulating awetting composition by combining the primary and secondary constituentsin pre-determined proportion; admixing a major portion of water with aminor portion of the wetting composition to constitute an aqueoussolution as a second medium; and dispersing one of said first and secondmediums intimately with the other of said mediums to effectively removecarbonaceous matter from the first medium to the second medium.
 54. Awetting composition useful in treating diesel exhaust emission gases toreduce the concentration of particulate matter and/or carbon monoxide,the composition comprising: water; a chemical hydrocarbon cleanercomprising at least one component selected from the group consisting ofdetergents, soaps, surfactants and mixtures thereof; and a defoamingagent.
 55. The wetting composition of claim 54 wherein the compositionis phosphate-free.
 56. The wetting composition of claim 54 wherein thecomposition is nitrate-free.
 57. The wetting composition of claim 54wherein the chemical hydrocarbon cleaner is low-foaming.
 58. The wettingcomposition of claim 54 wherein the chemical hydrocarbon cleanercomprises at least one surfactant selected from the group consisting ofanionic surfactants, cationic surfactants, nonionic surfactants,amphoteric surfactants and mixtures thereof.
 59. The wetting compositionof claim 58 further comprising an organic solvent.
 60. The wettingcomposition of claim 59 wherein the chemical hydrocarbon cleanercomprises an anionic surfactant.
 61. The wetting composition of claim 60wherein the anionic surfactant is selected from alkylether sulfates,alkyl sulfates and mixtures thereof.
 62. The wetting composition ofclaim 59 wherein the chemical hydrocarbon cleaner comprises anamphoteric surfactant.
 63. The wetting composition of claim 59 whereinthe chemical hydrocarbon cleaner comprises a nonionic surfactant. 64.The wetting composition of claim 63 wherein the nonionic surfactant isselected from the group consisting of ethoxylated alcohol, alkanolaminesand mixtures thereof.
 65. The wetting composition of claim 64 whereinthe nonionic surfactant comprises an ethoxylated nonylphenol.
 66. Thewetting composition of claim 65 wherein the nonionic surfactantcomprises a mixture of an ethoxylated nonylphenol and an alkanolamine.67. The wetting composition of claim 66 wherein the nonionic surfactantcomprises a mixture of an nonoxynol 10 and monoethanolamine.
 68. Thewetting composition of claim 65 wherein the organic solvent comprises analkylene glycol ether.
 69. The wetting composition of claim 68 whereinthe organic solvent comprises dipropylene glycol methyl ether.
 70. Thewetting composition of claim 65 wherein the defoaming agent is selectedfrom petroleum-based antifoams, silicone-based antifoams and mixturesthereof.
 71. The wetting composition of claim 70 wherein the defoamingagent comprises a silicon-based antifoam.
 72. The wetting composition ofclaim 71 wherein the silicon-based anti-foam comprises anorganosiloxane.
 73. The wetting composition of claim 72 wherein thesilicon-based anti-foam comprises polydimethylsiloxane.
 74. The wettingcomposition of claim 65 further comprises a coupling agent.
 75. Thewetting composition of claim 74 wherein the coupling agent comprisestetrasodium EDTA.
 76. The wetting composition of 65 wherein the chemicalhydrocarbon cleaner comprises a soap formed by saponifying a tall oilfatty acid with a caustic comprising an alkanolamine.
 77. A wettingcomposition useful in treating diesel exhaust emission gases to reducethe concentration of particulate matter and/or carbon monoxide, thecomposition comprising: water; a chemical hydrocarbon cleaner comprisingethoxylated nonylphenol nonionic surfactant and a soap formed bysaponifying a tall oil fatty acid with monoethanolamine; an organicsolvent comprising dipropylene glycol methyl ether; a coupling agentcomprising tetrasodium EDTA; and a defoaming agent comprising asilicone-based antifoam.
 78. The wetting composition of claim 77 whereinthe ethoxylated nonylphenol nonionic surfactant comprises nonoxynol 10.79. The wetting composition of claim 78 wherein the silicone-basedantifoam comprises a polydimethylsiloxane.
 80. A wetting compositionuseful in treating diesel exhaust emission gases to reduce theconcentration of particulate matter and/or carbon monoxide, thecomposition comprising: at least about 35% by weight water; a chemicalhydrocarbon cleaner comprising an ethoxylated nonylphenol nonionicsurfactant and a soap formed by saponifying a tall oil fatty acid withmonoethanolamine, wherein the composition comprises from about 10% toabout 30% by weight ethoxylated nonylphenol nonionic surfactant, fromabout 2% to about 8% by weight tall oil fatty acid and from about 1% toabout 5% by weight monoethanolamine; an organic solvent comprisingdipropylene glycol methyl ether, wherein the composition comprises fromabout 5% to about 15% by weight dipropylene glycol methyl ether; acoupling agent comprising tetrasodium EDTA, wherein the compositioncomprises at least about 0.5% by weight tetrasodium EDTA; and adefoaming agent comprising a silicon-based antifoam, wherein thecomposition comprises at least about 1% by weight silicon-basedantifoam.
 81. The wetting composition of claim 80 wherein theethoxylated nonylphenol nonionic surfactant comprises nonoxynol
 10. 82.The wetting composition of claim 80 wherein the silicone-based antifoamcomprises a polydimethylsiloxane.